The meaning of specific error codes is known only to Philips themselves, but 'AB' errors are to do with the analogue board circuitry and unfortunately this signals that the machine may require a factory repair. However you have nothing to lose by performing a firmware upgrade, which cured the problem for some.
Make sure you use the correct firmware, depending on whether your machine is a Mk I or II. Note that ff9o is the only firmware you can use for the former.
Firmware upgrade procedure